The field of the invention is semiconductor devices and particularly junction field-effect devices such as junction field-effect transistors.
Modification of basic junction field-effect devices to improve performance and increase their applicability to integrated circuits has been an area of active investigation. However, in all junction field-effect devices of the past, gate control of the transistor has been provided by using a semiconductor material having an impurity concentration which is opposite to that which has been utilized for the drain and source electrodes and consequently the channel. This has required that the gate material be isolated from the surrounding substrate if it is to be useful in integrated circuits. In addition, it has prevented enhancement mode junction field-effect transistors from being constructed; that is, a device whose channel current is zero with the gate and source electrodes connected together. Devices of the past have been controlled by changes in the applied potential across the junction. It is not believed that any prior art device has been disclosed or suggested in which merged depletion regions are used for isolation and which is operated and controlled by merging depletion regions or otherwise affecting the charge balance across the channel junction. Nor is any prior art device known which has all connections formed of the same conductivity type material with no intervening isolating regions.